Not even GNOME itself could ignore the GNOME 3 criticism for much longer. "As part of the planning for the DropOrFixFallbackMode feature, we've decided that we will compile a list of supported gnome-shell extensions. This will be a small list, focused on just bringing back some central 'classic' UX elements: classic alt tab, task bar, min/max buttons, main menu. To ensure that these extensions keep working, we will release them as a tarball, just like any other module."

Don't know about RHEL 7, but Fedora 18 Beta has released with Gnome 3.6 as default DE. However, MATE, KDE, XFCE, LXDE, and something called SoaS (Sugar on a Stick) are options. Personally, I'm torrenting F18 Beta with XFCE ... cool, the dl just finished as I write!